Truecaller verified tick mark will appear on its own, you don’t really need to do anything about it. Once the Truecaller system has enough confidence that your name is accurate, the blue verified tick mark will appear on your Truecaller profile. So just keep your profile accurate and the blue tick will appear soon.
To learn more about verified badges click here: https://blog.truecaller.com/2014/01/10/truecaller-verified-badge/
To find out if your number has a Verified Badge or not, please search your number on Truecaller.com.
Note: Please note that Truecaller Verified Business Caller ID with a green badge is a subscription-based paid business product. For more details visit business.truecaller.com